The present invention relates to tetrakisfluoroalkylborate salts, methods of producing same, and their use in electrolytes, batteries, capacitors, supercapacitors, and galvanic cells.
In recent years, the spreading of portable electronic devices such as laptop and palmtop computers, cell telephones, or video cameras and thus, the demand for light-weight and high-performance batteries has dramatically increased worldwide.
In view of such rapidly increasing demand for batteries and the associated ecological problems, the development of rechargeable batteries having long service life has become more and more important.
Starting in the early nineties, rechargeable lithium ion batteries have been traded commercially. Most of these batteries work with lithium hexafluorophosphate as conducting salt. However, this lithium salt is a compound which is extremely sensitive to hydrolysis and has low thermal stability and therefore, due to such properties of this salt, appropriate batteries can only be produced by means of highly expensive and thus, exceedingly cost-intensive processes. Also, the sensitivity of this lithium salt reduces the service life and the performance of such lithium batteries, impairing their use under extreme conditions, such as high temperatures.
Therefore, numerous attempts have been made to provide lithium salts having improved properties. Thus, U.S. Pat. Nos. 4,505,997 and 5,273,840 describe the use of lithium [tris(trifluoromethylsulfonyl)imide] or lithium [tris(trifluoromethylsulfonyl)methanide] salts as conducting salts in batteries. Both of these salts have high anodic stability, forming solutions of high conductivity with organic carbonates. However, lithium bis(trifluoromethylsulfonyl)imide has the drawback of insufficient passivation of the aluminum metal functioning as cathodic current conductor in lithium batteries. On the other hand, the production and purification of lithium tris(trifluoromethylsulfonyl)methanide is only possible with exceedingly high efforts, so that the use of this salt as conducting salt in batteries massively increases the production cost of such lithium batteries.
Another lithium salt used in battery cells is lithium tetrafluoroborate. However, this salt has a relatively low solubility in most solvents, so that solutions thereof generally have low ionic conductivities.
It is therefore the object of the present invention to provide conducting salts that would exhibit no or only slight evidence of hydrolytic decomposition over a long period of time. Furthermore, these conducting salts also should have high ionic conductivity, high thermal stability and from good to very good solubility in usual solvents. Another object of the present invention is to improve or enhance the service life and performance of primary and secondary batteries, capacitors, supercapacitors and/or galvanic cells.
Said object is accomplished by providing tetrakisfluoroalkylborate salts of general formula (I)
Mn+([BR4]xe2x88x92)nxe2x80x83xe2x80x83(I)
wherein
Mn+ is a univalent, bivalent, or trivalent cation, each of the ligands R are the same and straight-chained or branched and represent (Cxf2x+1), with 1xe2x89xa6xxe2x89xa68, and n=1, 2 or 3.
Preferred are those tetrakisfluoroalkylborate salts of the invention having the general formula (I), wherein MMn+ is an alkali metal cation, preferably a lithium, sodium or potassium cation, and more preferably a lithium cation, a magnesium or aluminum cation.
Furthermore, those tetrakisfluoroalkylborate salts of general formula (I) are preferred wherein the Mn+ cation is an organic cation, preferably a nitrosyl cation, a nitryl cation, or a cation of general formula [N(R7)4]+, [P(N(R7)2)kR4xe2x88x92k]+, with 0xe2x89xa6kxe2x89xa64, or [C(N(R7)2)3]+, wherein each of the substituents R7 are the same or different, representing
H,
CoF2o+1xe2x88x92pxe2x88x92qHpAq, or
A,
wherein
1xe2x89xa6oxe2x89xa610, 0pxe2x89xa62o+1, 0xe2x89xa6qxe2x89xa62o+1, preferably 1xe2x89xa6oxe2x89xa66, 0xe2x89xa6pxe2x89xa62o+1, and 0xe2x89xa6qxe2x89xa62o+1, and A represents an aromatic residue optionally having heteroatoms, or a preferably 5- or 6-membered cycloalkyl residue.
All of the aromatic, heteroaromatic or cycloaliphatic compounds well-known to those skilled in the art and suitable in the preparation of [N(R7)4]+, [P(N(R7)2)kR4xe2x88x92k]+, with 0xe2x89xa6kxe2x89xa64, or [C(N(R7)2)3]+ cations can be used as aromatic or cycloaliphatic residue A optionally including heteroatoms.
Preferably, A represents a 5- or 6-membered aromatic or cycloaliphatic residue optionally including nitrogen and/or sulfur and/or oxygen atoms, more preferably a phenyl or pyridine residue.
In another preferred embodiment of the present invention, the cation Mn+ is a heteroaromatic cation selected from the group of heteroaromatic cations of general formulas (II) to (IX): 
The residues R1 to R6, each of which may be the same or different, represent H, a halogen, preferably fluorine, or a C1-8 alkyl residue optionally substituted by F, Cl, N(CaF(2a+1xe2x88x92b)Hb)2, O(CaF(2a+1xe2x88x92b)Hb), SO2(CaF(2a+1xe2x88x92b)Hb), or CaF(2a+1xe2x88x92b)Hb substituents wherein 1xe2x89xa6axe2x89xa66,and 0xe2x89xa6bxe2x89xa62a+1.
Likewise, two of the residues R1 to R6 together may represent a C1-8 alkyl residue optionally substituted by F, Cl, N(CaF(2a+1xe2x88x92b)Hb)2, O(CaF(2a+1xe2x88x92b)Hb), SO2(CaF(2a+1xe2x88x92b)Hb), or CaF(2a+1xe2x88x92b)Hb substituents wherein 1xe2x89xa6axe2x89xa66, and 0xe2x89xa6bxe2x89xa62a+1.
Also preferred are tetrakisfluoroalkylborate salts of general formula (I) wherein each of the ligands R are the same, representing (CxF2x+1), and x=1 or 2. Those tetrakisfluoroalkylborate salts are particularly preferred wherein each of the ligands R are the same, representing a CF3 residue.
The salts of the invention having the general formula (I) can be used both in pure form and in the form of mixtures thereof as conducting salts in electrolytes, primary and secondary batteries, capacitors, supercapacitors and/or galvanic cells. As conducting salts, it is also possible to use the salts according to the invention in mixture with other lithium salts well-known to those skilled in the art.
They can be used in amounts of between 1 and 99% in combination with other conducting salts that find use in electrochemical cells. For example, conducting salts selected from the group of LiPF6, LiBF4, LiClO4, LiAsF6, LiCF3SO3, LiN(CF3SO2)2, LiC(CF3SO2)3 and mixtures of at least two of these compounds are suitable.
The salts of formula (I) and mixtures thereof can also be used in electrolytes for electrochemical cells.
The electrolytes may also include organic isocyanates (DE 100 42 149) to reduce the water content.
Compounds of general formula
[([R1(CR2R3)k]lAx)yKt]+(CF3)2Nxe2x80x94
wherein
Kt represents N, P, As, Sb, S, Se,
A represents N, P, P(O), O, S, S(O), SO2, As, As(O), Sb, Sb(O),
R1, R2 and R3, same or different, represent H, halogen, substituted and/or unsubstituted alkyl CnH2n+1, substituted and/or unsubstituted alkenyl having 1-18 carbon atoms and one or more double bonds, substituted and/or unsubstituted alkynyl having 1-18 carbon atoms and one or more triple bonds, substituted and/or unsubstituted cycloalkyl CmH2mxe2x88x921, mono- or polysubstituted and/or unsubstituted phenyl, substituted and/or unsubstituted heteroaryl,
A may be included at different positions in R1, R2 and/or R3,
Kt may be included in cyclic or heterocyclic rings; the groups bound to Kt may be the same or different, with
may also be included (DE 99 41 566). The method of preparing these compounds is characterized in that an alkali salt of general formula
D+(CF3)2Nxe2x88x92
with D+ selected from the group of alkali metals, is reacted in a polar organic solvent with a salt of general formula
[([R1(CR2R3)k]lAx)yKt]+Exe2x88x92
wherein
Kt, A, R1, R2, R3, k, l, x, and y have the above-stated meanings, and Exe2x88x92 represents Fxe2x88x92, Clxe2x88x92, Brxe2x88x92, Ixe2x88x92, BF4xe2x88x92, ClO4xe2x88x92, AsF6xe2x88x92, SbF6xe2x88x92, or PF6xe2x88x92.
The mixtures according to the invention may also be included in electrolytes comprising compounds of formula
Xxe2x80x94(CYZ)mxe2x80x94SO2N(CR1R2R3)2,
with
X H,F,Cl,CnF2n+1, CnF2nxe2x88x921, (SO2)kN(CR1R2R3)2,
Y H,F,Cl
Z H,F,Cl
R1,R2,R3 Hand/or alkyl, fluroalkyl, cycloalkyl,
m 0xe2x88x929, and if X=H, mxe2x89xa00,
n 1xe2x88x929,
k 0 if m=0, and k=1xe2x88x929,
prepared by reacting partially fluorinated or perfluorinated alkylsulfonyl fluorides with dimethylamine in organic solvents (DE 199 53 051).
Lithium complex salts of formula 
wherein
R1 and R2 are the same or different, optionally bound directly to each other by a single or double bond, each one alone or together representing an aromatic ring from the group of phenyl, naphthyl, anthracyl or phenanthryl, which may be unsubstituted or from mono- to hexasubstituted by alkyl (C1-C6), alkoxy groups (C1-C6), or halogen (F, Cl, Br), or
each one alone or together representing an aromatic heterocyclic ring from the group of pyridyl, pyrazyl or pyrimidyl, which may be unsubstituted or from mono- to tetrasubstituted by alkyl (C1-C6), alkoxy groups (C1-C6), or halogen (F, Cl, Br), or
each one alone or together representing an aromatic ring from the group of hydroxybenzenecarboxyl, hydroxynaphthalenecarboxyl, hydroxybenzenesulfonyl, and hydroxynaphthalenesulfonyl, which may be unsubstituted or from mono- to tetrasubstituted by alkyl (C1-C6), alkoxy groups (C1-C6), or halogen (F, Cl, Br),
R3 to R6, each one alone or in pairs, optionally bound directly to each other by a single or double bond, may represent the following:
1. alkyl (C1-C6), alkoxy (C1-C6), or halogen (F, Cl, Br),
2. an aromatic ring from the groups of phenyl, naphthyl, anthracyl, or phenanthryl, which may be unsubstituted or from mono- to hexasubstituted by alkyl (C1-C6), alkoxy groups (C1-C6), or halogen (F, Cl, Br),
pyridyl, pyrazyl or pyrimidyl, which may be unsubstituted or from mono- to tetrasubstituted by alkyl (C1-C6), alkoxy groups (C1-C6), or halogen (F, Cl, Br), prepared using the following method (DE 199 32 317)
a) 3-, 4-, 5-, 6-substituted phenol in a suitable solvent is added with chlorosulfonic acid,
b) the intermediate from a) is reacted with chlorotrimethylsilane, filtrated and subjected to fractionated distillation,
c) the intermediate from b) is reacted with lithium borate tetramethanolate in a suitable solvent, and the final product is isolated therefrom,
may also be included in the electrolyte.
Electrolytes having complex salts of general formula (DE 199 51 804)
Mx+[EZ]x/yyxe2x88x92
wherein
x, y represent 1, 2, 3, 4, 5, 6,
Mx+ represents a metal ion,
E represents a Lewis acid selected from the group of BR1R2R3, AlR1R2R3, PR1R2R3R4R5, AsR1R2R3R4R5, VR1R2R3R4R5,
R1 to R5, same or different, optionally bound directly to each other by a single or double bond, each one alone or together may represent
a halogen (F, Cl, Br),
an alkyl or alkoxy residue (C1-C8) which may be partially or completely substituted by F, Cl, Br,
an aromatic ring from the group of phenyl, naphthyl, anthracyl, or phenanthryl, optionally bound via oxygen, which may be unsubstituted or from mono- to tetrasubstituted by alkyl (C1-C8) or F, Cl, Br,
an aromatic heterocyclic ring from the group of pyridyl, pyrazyl or pyrimidyl, optionally bound via oxygen, which may be unsubstituted or from mono- to tetrasubstituted by alkyl (C1-C8) or F, Cl, Br, and
Z represents OR6, NR6R7, CR6R7R8, OSO2R6, N(SO2R6)(SO2R7),
C(SO2R6)(SO2R7)(SO2R8), OCOR6,
wherein
R6 to R8 are the same or different, optionally bound directly to each other by a single or double bond, each one alone or together representing hydrogen or having the meaning like R1 to R5,
prepared by reacting an appropriate boron or phosphorus/Lewis acid/solvent adduct with a lithium or tetraalkylammonium imide, methanide or triflate, can also be used.
Borate salts (DE 199 59 722) of general formula 
wherein
M represents a metal ion or a tetraalkylammonium ion,
x, y represent 1, 2, 3, 4, 5, or 6,
R1 to R4, same or different, represent alkoxy or carboxy residues (C1-C8) optionally bound directly to each other by a single or double bond, may also be included.
These borate salts are prepared by reacting lithium borate tetraalcoholate or a 1:1 mixture of lithium alcoholate and a boric acid ester in an aprotic solvent with a suitable hydroxy or carboxy compound at a ratio of 2:1 or 4:1.
Additives such as silane compounds of general formula
SiR1R2R3R4
with
R1 to R4 H,
CyF2y+1xe2x88x92zHz,
OCyF2y+1xe2x88x92zHz,
OC(O)CyF2y+1xe2x88x92zHz,
OSO2CyF2y+1xe2x88x92zHz,
and
1xe2x89xa6xxe2x89xa66,
1xe2x89xa6yxe2x89xa68, and
0xe2x89xa6zxe2x89xa62y+1,
and
R1-R4, same or different, representing an aromatic ring from the group of phenyl, naphthyl, which may be unsubstituted or mono- or polysubstituted by F, CyF2y+1=zHz or OCyF2y+1xe2x88x92zHz, OC(O)CyF2y+1xe2x88x92zHz, OSO2CyF2y+1xe2x88x92zHz, N(CnF2n+1xe2x88x92zHz)2, or representing a heterocyclic aromatic ring from the group of pyridyl, pyrazyl or pyrimidyl, each of which may be substituted by F, CyF2y+1xe2x88x92zHz or OCyF2y+1xe2x88x92zHz, OC(O)CyF2y+1xe2x88x92zHz, OSO2CyF2y+1xe2x88x92zHz, N(CnF2n+1xe2x88x92zHz)2 (DE 100 27 626), may also be included.
The compounds according to the invention can also be used in electrolytes including lithium fluoroalkylphosphates of following formula
Li+[PFx(CyF2y+1xe2x88x92zHz)6xe2x88x92x]xe2x88x92
wherein
1xe2x89xa6xxe2x89xa65,
3xe2x89xa6yxe2x89xa68,
0xe2x89xa6zxe2x89xa62y+1,
and the ligands (CyF2y+1xe2x88x92zHz) may be the same or different, with compounds of general formula
Li+[PFa(CHbFc(CF3)d)e]xe2x88x92
wherein a is an integer of from 2 to 5, b=0 or 1, c=0 or 1, d=2, and e is an integer of from 1 to 4, with the proviso that b and c do not simultaneously represent zero, and the sum of a+e=6, and the ligands (CHbFc(CF3)d) may be the same or different, being excluded (DE 100 08 955). The method of preparing lithium fluoroalkylphosphates is characterized in that at least one compound of general formula
wherein
0 less than m less than 2,3 less than n less than 8, and 0 less than o less than 4, is fluorinated by electrolysis in hydrogen fluoride, the mixture of fluorination products thus obtained is separated by extraction, phase separation and/or distillation, and the fluorinated alkylphosphorane thus obtained is reacted in an aprotic solvent or mixture of solvents with lithium fluoride under exclusion of moisture, and the resulting salt is purified and isolated according to conventional methods.
The compounds according to the invention may also be used in electrolytes including salts of formula
Li[P(OR1)a(OR2)b(OR3)c(OR4)dFe]
wherein
0xe2x89xa6a+b+c+dxe2x89xa65, and a+b+c+d+e=6, and R1 to R4 independently are alkyl, aryl or heteroaryl residues, and at least two of R1 to R4 may be bound directly to each other by a single or double bond (DE 100 16 801). These compounds are prepared by reacting phosphorus(V) compounds of general formula
P(OR1)a(OR2)b(OR3)c(OR4)dFe
wherein
0xe2x89xa6a+b+c+dxe2x89xa65, and a+b+c+d+e=5, and R1 to R4 have the above-stated meanings, with lithium fluoride in the presence of an organic solvent.
Ionic liquids of general formula
K+Axe2x88x92
wherein
K+ represents a cation selected from the group of 
wherein
R1 to R5 are the same or different, optionally bound directly to each other by a single or double bond, each one alone or together representing the following:
H,
halogen,
alkyl residue (C1-C8) which may be partially or completely substituted by F, Cl, N(CnF(2n+1xe2x88x92x)Hx)2, O(CnF(2n+1xe2x88x92x)Hx), SO2(CnF(2n+1xe2x88x92x)Hx), CnF(2n+1xe2x88x92x)Hx, with 1 less than n less than 6, and 0 less than x less than 13, and
Axe2x88x92 represents an anion selected from the group of
[B(OR1)n(OR2)m(OR3)o(OR4)p]xe2x88x92
with
0xe2x89xa6n, m, o, pxe2x89xa64, and
m+n+o+p=4,
wherein
R1 to R4 are different, or pairs thereof are the same, optionally bound directly to each other by a single or double bond, each one alone or together representing an aromatic ring from the group of phenyl, naphthyl, anthracyl, or phenanthryl, which may be unsubstituted or mono- or polysubstituted by CnF(2n+1xe2x88x92x)Hx, with 1 less than n less than 6, and 0 less than xxe2x89xa613, or halogen (F, Cl, Br), or
representing an aromatic heterocyclic ring from the group of pyridyl, pyrazyl or pyrimidyl, which may be unsubstituted or mono- or polysubstituted by CnF(2n+1xe2x88x92x)Hx, with 1 less than n less than 6, and 0 less than xxe2x89xa613, or halogen (F, Cl, Br), or
representing an alkyl residue (C1-C8) which may be partially or completely substituted by additional groups, preferably F, Cl, N(CnF(2n+1xe2x88x92x)Hx)2, O(CnF2n+1xe2x88x92x)Hx), SO2(CnF(2n+1xe2x88x92x)Hx), CnF(2n+1xe2x88x92x)Hx, with 1 less than nxe2x89xa66, and 0 less than xxe2x89xa613,
or wherein
OR1 to OR4, each one alone or together, represent an aromatic or aliphatic carboxyl, dicarboxyl, oxysulfonyl, or oxycarboxyl residue which may be partially or completely substituted by additional groups preferably F, Cl, N(CnF(2n+1xe2x88x92x)Hx)2,
O(CnF(2n+1xe2x88x92x)Hx), SO2(CnF(2n+1xe2x88x92x)Hx), CnF(2n+1xe2x88x92x)Hx, with 1 less than n less than 6, and 0 less than xxe2x89xa613 (DE 100 26 565),
may be included in the electrolyte.
Ionic liquids K+Axe2x88x92 wherein K+ is as defined above and A represents an anion selected from the group of
[PFx(CyF2y+1xe2x88x92zHz)6xe2x88x92x]xe2x88x92
with
1xe2x89xa6xxe2x89xa66,
1xe2x89xa6yxe2x89xa68, and
0xe2x89xa6zxe2x89xa62y+1,
may also be included (DE 100 27 995).
The compounds according to the invention can be used in electrolytes for electrochemical cells including an anode material which consists of coated metal cores selected from the group of Sb, Bi, Cd, In, Pb, Ga, and tin, or alloys thereof (DE 100 16 024). The process for producing such anode material is characterized in that
a) a suspension or sol of the core metal or alloy in urotropine is prepared,
b) the suspension is emulsified with C5-C12 hydrocarbons,
c) the emulsion is precipitated on the metal or alloy core, and
d) the metal hydroxides or oxyhydroxides are converted to the corresponding oxides by tempering.
The compounds according to the invention can also be used in electrolytes for electrochemical cells with cathodes made of common lithium intercalation and insertion compounds, but also with cathode materials consisting of lithium mixed oxide particles which are coated with one or more metal oxides (DE 199 22 522) by suspending the particles in an organic solvent, adding to the suspension a solution of a hydrolyzable metal compound and a hydrolyzing solution, and subsequently filtrating, drying and optionally calcining the coated particles. Said materials may also consist of lithium mixed oxide particles coated with one or more polymers (DE 199 46 066), obtained using a process wherein the particles are suspended in a solvent, and the coated particles subsequently are filtrated off, dried and optionally calcined. Likewise, the compounds according to the invention can be used in systems including cathodes comprised of lithium mixed oxide particles having one or more coatings of alkali metal compounds and metal oxides (DE 100 14 884). The process for producing these materials is characterized in that the particles are suspended in an organic solvent, an alkali metal salt compound suspended in an organic solvent is added, metal oxides dissolved in an organic solvent are added, the suspension is added with a hydrolyzing solution, and the coated particles subsequently are filtrated off, dried and calcined. Likewise, the compounds according to the invention can be used in systems including anode materials with doped tin oxide (DE 100 25 761). Such an anode material is prepared by
a) adding urea to a tin chloride solution,
b) adding the solution with urotropine and a suitable doping compound,
c) emulsifying the sol thus obtained in petroleum ether,
d) washing the resulting gel, and removing the solvent by suction, and
e) drying and tempering the gel.
Likewise, the compounds according to the invention can be used in systems including anode materials with reduced tin oxide (DE 100 25 762). This anode material is produced by
a) adding urea to a tin chloride solution,
b) adding the solution with urotropine,
c) emulsifying the sol thus obtained in petroleum ether,
d) washing the resulting gel, and removing the solvent by suction,
e) drying and tempering the gel, and
f) exposing the resulting SnO2 to a stream of reducing gas in a gas-feedable oven.
Preferably, the salts according to the invention are used as conducting salts in their pure form, because particularly good reproducibility of the electrochemical properties can be ensured in this way.
The invention is also directed to a method of producing the tetrakisfluoroalkylborate salts of the invention having the general formula (I) wherein the ligands R each are identical, representing a CF3 residue.
In this method, at least one salt of general formula (X)
Mn+([B(CN)4]xe2x88x92)nxe2x80x83xe2x80x83(X)
wherein Mn+ and n have the above-stated meanings, is fluorinated by reacting with at least one fluorinating agent in at least one solvent, and the fluorinated compound of general formula (I) thus obtained is purified and isolated according to methods well-known to those skilled in the art.
Immediately subsequent to fluorination, the tetrakisfluoroalkylborate salts frequently have a purity of  greater than 99%. If necessary, further purification of the salts can be effected according to methods well-known to those skilled in the art, e.g. by recrystallization in a suitable solvent or mixture of solvents. A person skilled in the art may select suitable solvents or mixtures of solvents by means of simple preliminary tests.
The compounds of general formula (X) can be synthesized in analogy to the method published in E. Bernhardt, G. Henkel, H. Willner, Z. Anorg. Allg. Chem. 2000, Vol. 626, p. 560. This citation is hereby incorporated by reference and is deemed to be part of the disclosure.
In the method according to the invention, the reaction with the fluorinating agent preferably is effected at a temperature ranging from xe2x88x9280 to +20xc2x0 C., more preferably at a temperature ranging from xe2x88x9260 to 0xc2x0 C.
In the method according to the invention, it is preferred to use fluorine, chlorine fluoride, chlorine trifluoride, chlorine pentafluoride, bromine trifluoride, bromine pentafluoride, or a mixture of at least two of these fluorinating agents as suitable fluorinating agents. The use of chlorine fluoride, chlorine trifluoride or a mixture of at least two fluorinating agents containing chlorine fluoride and/or chlorine trifluoride is particularly preferred.
It is preferred to use hydrogen fluoride, iodine pentafluoride, dichloromethane, chloroform, or a mixture of at least two of these solvents as suitable solvent in the fluorination of the salts of general formula (X). It is particularly preferred to use hydrogen fluoride as solvent.
The tetrakisfluoroalkylborate salts of general formula (I) are also suitable for use in solid electrolytes. In the meaning of the invention, solid electrolytes are understood to be polymer electrolytes normally having an optionally crosslinked polymer and a conducting salt, as well as gel electrolytes which, in addition to an optionally crosslinked polymer and a conducting salt, include at least one solvent.
The present invention therefore is also directed to a mixture including
a) at least one tetrakisfluoroalkylborate salt of general formula (I), and
b) at least one polymer.
Mixtures in the meaning of the present invention include pure mixtures of components a) and b), mixtures wherein the salt of component a) is included in the polymer of component b), and mixtures wherein chemical and/or physical bonds exist between the salt of component a) and the polymer of component b).
In a preferred embodiment of the present invention, the mixture of the invention includes from 5 to 99 wt.-% of component a) and from 95 to 1 wt.-% of component b), more preferably from 60 to 99 wt.-% of component a) and from 40 to 1 wt.-% of component b). Each of the specified weight ratios relates to the sum of components a) and b).
As component b), the mixture according to the invention preferably includes a homopolymer or copolymer of unsaturated nitrites, preferably acrylonitrile, vinylidenes, preferably vinylidene difluoride, acrylates, preferably methyl acrylate, methacrylates, preferably methyl methacrylate, cyclic ethers, preferably tetrahydrofuran, alkylene oxides, preferably ethylene oxide, siloxane; phosphazene, alkoxysilanes, or an organically modified ceramic, or a mixture of at least two of the above-mentioned homopolymers and/or-copolymers and optionally at least one organically modified ceramic.
Preferably, inorganic-organic hybrid polymers are possible as organically modified ceramics, which polymers are obtained by hydrolysis and fusion of organically modified silicon alkoxides and subsequent crosslinking of the crosslinkable groups fixed on the inorganic backbone. For example, appropriate organically modified ceramics are being marketed under the name of ORMOCERE(copyright).
More preferably, component b) is a homopolymer or copolymer of vinylidene difluoride, acrylonitrile, methyl (meth)acrylate, tetrahydrofuran, and especially preferably a homopolymer or copolymer of vinylidene difluoride.
These homo- and copolymers of vinylidene difluoride are being marketed under the names of Kynar(copyright) and Kynarflex(copyright) by Atofina Chemicals; Inc., and under the name of Solef(copyright) by the Solvay Company.
The polymers used according to the invention may also be at least partially crosslinked. Crosslinking can be effected according to conventional methods well-known to those skilled in the art, using well-known crosslinking agents. Crosslinking may also be effected in the presence of component a) and optionally additional components.
In addition to the tetrakisfluoroalkylborate salts of general formula (I) and the polymers, the mixture according to the invention may include a solvent or a mixture of solvents comprised of two or more solvents.
Preferred solvents are organic carbonates, preferably ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, or methyl propyl carbonate, organic esters, preferably methyl formate, ethyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, xcex3-butyrolactone, organic ethers, preferably diethyl ether, dimethoxyethane, diethoxyethane, organic amides, preferably dimethylformamide or dimethylacetamide, sulfur-containing solvents, preferably dimethylsulfoxide, dimethyl sulfite, diethyl sulfite, or propanesultone, aprotic solvents, preferably acetonitrile, acrylonitrile, or acetone, or at least partially fluorinated derivatives of the above-mentioned solvents, or mixtures of at least two of these solvents and/or fluorinated derivatives of these solvents.
The present invention also is directed to a method of producing the mixtures of the invention, according to which at least one of the above-mentioned tetrakisfluoroalkylborate salts of general formula (I) and at least one polymer and optionally at least one solvent are mixed together.
Preferably, the above components are mixed at elevated temperature, more preferably at 20 to 90xc2x0 C., with 40 to 60xc2x0 C. being particularly preferred, and these temperatures may vary depending on the components employed.
The present invention is also directed to the use of at least one tetrakisfluoroalkylborate salt according to the invention or of a mixture according to the invention in electrolytes, primary batteries, secondary batteries, capacitors, supercapacitors, and/or galvanic cells, optionally in combination with other well-known conducting salts and/or additives.
Furthermore, the tetrakisfluoroalkylborate salts according to the invention are suitable in the polymerization of olefins. They are also suitable in the production of catalytically active compounds wherein the tetrakisfluoroalkylborate anions function as counterions of the cationic catalysts. Therefore, the present invention is also directed to the use of the tetrakisfluoroalkylborate salts in the polymerization of olefins and in the production of catalysts.
The invention is also directed to electrolytes, primary and secondary batteries, capacitors, supercapacitors, and galvanic cells including at least one tetrakisfluoroalkylborate salt according to the invention having general formula (I) or a mixture according to the invention and optionally other conducting salts and/or additives. Other conducting salts and additives are known to those skilled in the art, e.g. from Doron Auerbach, Nonaqueous Electrochemistry, Marc Dekker Inc., New York, 1999; D. Linden, Handbook of Batteries, Second Edition, McGraw-Hill Inc., New York, 1995; as well as G. Mamantov and A. I. Popov, Chemistry of Nonaqueous Solutions, Current Progress, VCH Verlagsgesellschaft, Weinheim, 1994. These citations are hereby incorporated by reference and are deemed to be part of the disclosure.
The electrolytes according to the invention preferably include concentrations of the tetrakisfluoroalkylborate salts of the invention of from 0.01 to 3 mol/l, more preferably from 0.01 to 2 mol/l, with 0.1 to 1.5 mol/l being particularly preferred.
As solvents for the salts of the invention, the electrolyte preferably include organic carbonates, preferably ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, or methyl propyl carbonate, organic esters, preferably methyl formate, ethyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, ethyl butyrate, xcex3-butyrolactone, organic ethers, preferably diethyl ether, dimethoxyethane, diethoxyethane, organic amides, preferably dimethylformamide or dimethylacetamide, sulfur-containing solvents, preferably dimethylsulfoxide, dimethyl sulfite, diethyl sulfite, or propanesultone, aprotic solvents, preferably acetonitrile, acrylonitrile, or acetone, or at least partially fluorinated derivatives of the above-mentioned solvents, or mixtures of at least two of these solvents and/or fluorinated derivatives of these solvents.
The tetrakisfluoroalkylborate salts according to the invention and the mixtures of the invention are advantageous in that signs of decomposition in the presence of water are absent or nearly absent over a long period of time, and that they have from good to very good solubility in most solvents or mixtures of solvents.
Furthermore, they have high thermal stability and high chemical stability both in the solid and dissolved states. Thus, the salts and mixtures according to the invention are stable with respect to strong oxidants such as fluorine.
By virtue of these properties, electrolytes, batteries, capacitors, supercapacitors, and galvanic cells including these conducting salts can also be used under extreme conditions, such as high temperatures, with no adverse effects on their service life and performance by such conditions.
Furthermore, these batteries, capacitors, supercapacitors, and galvanic cells are remarkable for their highly constant voltage, unrestricted functionality over many charge/discharge cycles, as well as low production cost.
The use of the tetrakisfluoroalkylborate slats or mixtures according to the invention in large batteries, such as those used in electric road vehicles or hybrid road vehicles is also highly advantageous, because no toxic and strongly etching hydrogen fluoride will be formed upon damage of the batteries, e.g. in case of an accident, not even upon contact with water, e.g. humidity or fire-fighting water.
With reference to the examples, the invention will be illustrated below. These examples merely are intended to illustrate the invention and do not limit the general idea of the invention.
Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.
In the foregoing and in the following examples, all temperatures are set forth uncorrected in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.
The entire disclosure[s] of all applications, patents, and publications, cited above [or below], and of corresponding German Application No. 10055811.9, filed Nov. 10, 2000 is hereby incorporated by reference.